This Midcareer Investigator Award in Patient-Oriented Research (K24) application is in response to program announcement (PA-99-133) "Career Development Awards: Child Abuse and Neglect Research." Pediatric maltreatment-related PTSD is associated with dysregulation of biological stress systems, adverse brain maturation, and medial prefrontal cortical dysfunction. Building on previous work in developmental traumatology, the aim of this K24 is to investigate the psychobiology of effective PTSD treatment for sexually-abused children. The objectives of the career development plan are to: 1) develop expertise in evidence-based psychosocial treatments i.e., cognitive behavioral therapy (CBT) and combined psychopharmacologic interventions for maltreated children with PTSD, 2) further the candidate's knowledge of developmental and cognitive neuroscience emphasizing the integration and translation of brain imaging measurement as it relates to neurodiagnostic assessment and treatment, 3) increase the candidate's practical and empirical knowledge in the conduct and design of relevant clinical trials for treatment development including advanced research design, methodology and statistical aspects of conducting longitudinal studies and clinical trials, and 4) emphasize knowledge dissemination of the translational components of this research by mentoring junior colleagues in child abuse and neglect research. The research plan is linked to an ongoing study using brain imaging to help elucidate neurobiological markers in sexually abused children with PTSD. The objective of the research plan is a CBT treatment study using non-invasive biological markers (24 hour urinary concentrations of cortisol and catecholamines, MRS-based brain NAA concentrations of medial prefrontal cortex, and measures of neuropsychological functioning), in a pre-post design to investigate the pathogenesis of PTSD in 30 sexually abused children, ages 6 to 12 years. Exploring these biological markers in trauma-focused CBT + Sertraline and CBT + placebo is also proposed.